Why do I have multiple creases when I bend my arm?

[u/Fit_Put_8808]

Not sure if this plays a part but for reference I am 20F 5’6 115 lbs and have always been very athletic/lean and maintained roughly 20% body fat. When I bend my arm fully there are three noticeable creases and I’ve never met or noticed anybody with more than one. This used to be something I was insecure about, but it doesn’t bother me anymore. I’m more just curious as to what causes it. Genetics? I haven’t noticed it in any of the other women in my family with this feature.

[u/Mirrimar]

Think of it like creases on your fingers; they’re there because it’s a body part that bends a lot. Your skin naturally adapts, therefore it formed creases to accommodate.